//Get the current clip rectangle for the image. This is
// (one less than) the size of the image in both
// dimensions.
get_clip_rect(picA,
&upperLeftX,
&upperLeftY,
&lowerRightX,
&lowerRightY);
//Compute the width and the height from the coordinates
// of the diagonal corners of the clip rectangle.
width = lowerRightX + 1;
height = lowerRightY + 1;